alistair23-linux/include/linux/ioprio.h
Sebastian Andrzej Siewior 36436440cd block/ioprio: Use a helper to check for RT prio
A side-effect to the old code is that now SCHED_DEADLINE is also
recognized.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171004154901.26904-2-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-10 11:45:39 +02:00

80 lines
1.9 KiB
C

#ifndef IOPRIO_H
#define IOPRIO_H
#include <linux/sched.h>
#include <linux/sched/rt.h>
#include <linux/iocontext.h>
/*
* Gives us 8 prio classes with 13-bits of data for each class
*/
#define IOPRIO_CLASS_SHIFT (13)
#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
#define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
#define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK)
#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
#define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
/*
* These are the io priority groups as implemented by CFQ. RT is the realtime
* class, it always gets premium service. BE is the best-effort scheduling
* class, the default for any process. IDLE is the idle scheduling class, it
* is only served when no one else is using the disk.
*/
enum {
IOPRIO_CLASS_NONE,
IOPRIO_CLASS_RT,
IOPRIO_CLASS_BE,
IOPRIO_CLASS_IDLE,
};
/*
* 8 best effort priority levels are supported
*/
#define IOPRIO_BE_NR (8)
enum {
IOPRIO_WHO_PROCESS = 1,
IOPRIO_WHO_PGRP,
IOPRIO_WHO_USER,
};
/*
* Fallback BE priority
*/
#define IOPRIO_NORM (4)
/*
* if process has set io priority explicitly, use that. if not, convert
* the cpu scheduler nice value to an io priority
*/
static inline int task_nice_ioprio(struct task_struct *task)
{
return (task_nice(task) + 20) / 5;
}
/*
* This is for the case where the task hasn't asked for a specific IO class.
* Check for idle and rt task process, and return appropriate IO class.
*/
static inline int task_nice_ioclass(struct task_struct *task)
{
if (task->policy == SCHED_IDLE)
return IOPRIO_CLASS_IDLE;
else if (task_is_realtime(task))
return IOPRIO_CLASS_RT;
else
return IOPRIO_CLASS_BE;
}
/*
* For inheritance, return the highest of the two given priorities
*/
extern int ioprio_best(unsigned short aprio, unsigned short bprio);
extern int set_task_ioprio(struct task_struct *task, int ioprio);
#endif